class template specialization and inheritance

[Bill Baxter]

Edward Diener wrote:
> Bill Baxter wrote:
>> Edward Diener wrote:
>>> mki wrote:
>>>> Hello!
>>>>
>>>> I just discovered the template syntax of D. I am very exited about 
>>>> its simplicity compared to C++.
>>>>
>>>> Now I ran into a template behavior I do not understand. This code:
>>>  > snip...
>>>> class C(TT:A!(T)) {
>>>>     static void tellMe() {
>>>>         writefln("derived from A!(T).");
>>>>     }
>>>> }
>>>
>>> Huh ! What is T above ? I do not think that your use of T should be 
>>> legal. Are you sure you did not mean 'class C(TT:A!(TT)) { etc.' ?
>>
>> I think it's supposed to be legal using:
>>
>> class C(TT:A!(T), T)
> 
> This makes sense since T is another template parameter. In the original, 
> quoted further above, there was no second template parameter of T, which 
> should generate a compiler error.
> 
>>
>> That is, one template parameter can depend on another in a non-trivial 
>> way in theory. But I think the compiler has trouble with such things 
>> right now.
>>
>>  From what I understand that is the intended way to do C++ things like 
>> this in D:
>>
>> template <typename Z>
>> template class C { ... }
>>
>> // specialization for all Z == A<T> for template A and some T
>> template <typename T>
>>   template class C< A<T> > { ... }
> 
> If this is meant as C++ the second use of 'template' each time is 
> incorrect. 

Yeh, my C++ is a bit rusty from too much D. :-)

> Otherwise it is correct partial specialization syntax as you 
> mention. But notice that T is a template parameter in your C++ 
> equivalent example while in the OP's original which I cited as 
> erroneous, there is no T as a template parameter.

Right, I was just pointing out what I thought might have been the 
original poster's intention.

--bb